1. Technical Field
The present invention relates to a method for operating a combustion chamber for a gas turbine, the combustion chamber having a combustion space and a plurality of burners which are in each case arranged at an inlet of the combustion space.
2. Brief Description of the Related Art
To ensure that the minimum possible levels of pollutants are formed when a combustion chamber of this type is operating, the individual burners are supplied with a very lean fuel/oxidant mix, i.e., with relatively high λ values. To avoid thermo-acoustic pressure pulses, it is in principle possible to divide the burners of the combustion chamber into two burner groups and for the burners belonging to the two burner groups to be supplied with fuel/oxidant mixes which, although lean, have different λ values. Therefore, more fuel is available for conversion at the burners whose fuel/oxidant mix has a lower λ value, which leads to higher temperatures during the combustion reaction in the combustion space and therefore to a reduction in the pressure pulsation.
However, it has been found that when the combustion chamber is operating with two burner groups, the burners belonging to these groups, the burners of which are operated with different λ values, the total emission of pollutants increases, in particular the emission of NOx and visible flue gases (known as yellow plume), while at the same time the stability of the homogenous combustion reaction in the combustion space decreases.